Method of Preparing Conjugated Diene-Based Polymer and Apparatus for Preparing Conjugated Diene-Based Polymer

A method of preparing a conjugated diene-based polymer, comprising:

• adding a conjugated diene-based monomer, a catalyst, and a solvent to parallel polymerization reactors, wherein the parallel polymerization reactors include two or more polymerization reactors connected in parallel, and
• performing a polymerization reaction to prepare a first polymer solution including a first conjugated diene-based polymer;
• and
• adding the first polymer solution discharged from the parallel polymerization reactors to a series polymerization reactor connected in series to the parallel polymerization reactors and
• performing a polymerization reaction to prepare a second polymer solution including a second conjugated diene-based polymer,
• wherein after the polymerization reaction in the series polymerization reactor, gas produced by polymerization heat is condensed by a condenser in the series polymerization reactor and refluxed to the parallel polymerization reactors, and
• a reaction temperature of the series polymerization reactor is maintained to be lower than a reaction temperature of the parallel polymerization reactors by 10° C. or more.